Members with a lubricating property have been widely used recently. Slide members used in mechanical elements (shafts, bearings, cranks or the like) and recording members (magnetic tapes, magnetic discs, photo-electro magnetic discs, etc.) are examples of such members. A magnetic recording medium is mentioned in the following descriptions as an example of a conventional lubrication technology. Taking the place of coated magnetic recording media such as magnetic tape--in which a polyester film or the like is coated with solvent and a magnetic material such as ferrite powder--magnetic recording media with ferromagnetic metallic thin films formed on non-magnetic supports by a plating method, sputtering method, vacuum deposition method, ion plating method or the like have been in research as high density magnetic media.
For efficient operation, the magnetic recording medium located under the magnetic heads is required to run smoothly and stably at the stage of recording or playing magnetic signals even if the relative motion of the media to the heads is fast at such a stage.
Unfortunately, the high density magnetic media which are produced in the above-noted methods have poor anti-abrasion and running properties. Particularly, the ferromagnetic metallic thin film of the media produced in the above-noted methods cannot sustain rough conditions of the magnetic recording and playing processes. As a result, the media are likely to run with instability due to friction against the heads or the like, and the output of the media declines drastically because of abrasion and damage to the media or the generation of abrasion powder after running the media for many hours. Therefore, it has been required to apply a lubricating agent on the surfaces of magnetic recording media. In addition, in order to improve the recording density, it has been required to make the surfaces of the media as flat as possible. The surface roughness of the magnetic layer of a video tape currently has its center line average height around 0.02 micrometers; however, to further improve recording density of the magnetic recording media, the center line average height should be lowered by one digit. Contact area against the heads widens as the surface roughness of the media decreases, thus increasing the coefficient of friction. In this sense, an improved lubricating agent has been in demand.
Lubricating agents have been used for improving a running property and lowering the coefficient of friction of tapes, and the agents have been selected in consideration of the compatibility between the agents and binders, and of the mobility of a coating film. As a conventional lubricating agent, a long-chain hydrocarbon compound has been mainly used, and other kinds of lubricating agents are sometimes added to the agent (Denki Zairyo No Trypology by Realize Co., Ltd., p.185).
The conventional technology of lubricating ceramics, metals, resins, woods, inorganics, papers, fibers or the like is the same as the technology mentioned above.
There are solid and liquid conventional lubricating agents. The use of the solid lubricating agents, however, have been declining since it is difficult to coat the agents with a uniform thickness. The liquid lubricating agents, on the other hand, have been used for manufacturing lubricating films by spin-coating or dipping methods.
However, the thickness of the film formed by using the conventional liquid lubricating agents is at least five nanometers, and there is a limit on moving the medium close to the head. Therefore, the density and capacity of the medium is not likely to be improved. Although the lubricating film is needed especially for the convex surfaces of the magnetic recording medium to reduce the abrasion created by the friction between the head and the medium, the agent is likely to stay in the concave surfaces rather than on the convex surfaces. It is also difficult to control the supply of the liquid lubricating agent, and the agent is likely to scatter when a large quantity of it is supplied; as a result, reading and writing to magnetic records becomes difficult.